This invention relates to exhaust systems for moving vehicles. Specifically, this invention relates to an exhaust system baffling apparatus which is operative to dampen the noise level of an exhaust system and produce a unique and desirable exhaust sound.
Exhaust systems for moving vehicles are well known. In general, exhaust systems provide a means for dampening or muffling the noise level associated with exhaust gases exiting a combustion engine. However, different types of vehicles have different requirements for dampening the exhaust sound. For example, the object of racing vehicles is to move at a high rate of speed and win races. Because exhaust systems may limit the horsepower of an engine, racing vehicles often employ exhaust systems which minimize any loss of horsepower. As a result, racing exhaust systems tend to be excessively loud. On the other hand, passenger automobiles are designed to have a relatively low noise level for the exhaust system and typically employ mufflers to significantly dampen exhaust sounds. Other types of vehicles, such as sports cars, are often configured to have an exhaust sound with a noise level that is between the average automobile and the professional racing car.
Sports car enthusiasts often like to emphasize or xe2x80x9cshow offxe2x80x9d their exhaust systems. One method of emphasizing an exhaust system is to mount exhaust pipes in locations that are readily viewable. For example, many xe2x80x9cmuscle carsxe2x80x9d have exhaust pipes mounted on each side of the vehicle. Such side-mounted pipes may include a chromed outer surface to further emphasize the appearance of the exhaust system. Another method of emphasizing an exhaust system is to enhance the audible characteristics of the exhaust system. Such enhancements to the sound of an exhaust system may include raising the noise or volume level of the exhaust. Other enhancements may include changing the tone or range of tones of the exhaust system. For example, exhaust systems for xe2x80x9cmusclexe2x80x9d cars have been modified to produce deep, low frequency sounds. A deep sounding exhaust system is often intended to project to the listener that the car has a large and powerful engine. In addition, some exhaust sounds have such distinct qualities that manufacturers, such as Harley Davidson, have applied for trademark protection for the exhaust sounds of their vehicles.
For sports cars, various configurations of side pipe exhaust systems are available. However, the diversity of sounds produced by such systems is limited. As car enthusiasts desire methods of distinguishing their cars from the majority of other cars, there exists a need for an exhaust system which provides a unique sound that is deep in tone and dampened to meet legal and/or race track noise limitations.
Car enthusiasts often race their cars as a hobby. However, unlike their professional counterparts, car enthusiasts often require their cars to be used for general transportation in addition to racing. Thus there further exists a need for an exhaust system which both dampens the exhaust sounds to levels that are acceptable for general transportation needs, but minimizes the degradation of the power of the vehicle engine caused by restrictions to the flow of gases in the exhaust system.
Many modifications to exhaust systems require the replacement of large portions of the existing exhaust system to achieve the desired look, sound and performance for the vehicle. Unfortunately, such modifications may require custom bending of exhaust pipe and welding. Such modifications are both labor intensive and expensive. Thus, there exists a need for a method of modifying the sound and performance characteristics of an exhaust system, which can be performed relatively easily and quickly without the need for welding.
It is an object of an exemplary form of the present invention to provide an exhaust system for a vehicle.
It is a further object of an exemplary form of the present invention to provide an exhaust system which has a unique sound that is deep in tone.
It is a further object of an exemplary form of the present invention to provide an exhaust system with a maximum volume level which is acceptable for public street transportation purposes.
It is a further object of an exemplary form of the present invention to provide an exhaust system which reduces the exhaust system sound volume while minimizing degradation of engine power.
It is a further object of an exemplary form of the present invention to provide a method of modifying a pre-existing exhaust system to produce a unique exhaust sound that is deep in tone.
It is a further object of an exemplary form of the present invention to provide a method of modifying a pre-existing exhaust system to produce a maximum sound volume which is acceptable for public street transportation purposes.
It is a further object of an exemplary form of the present invention to provide a method of modifying a pre-existing exhaust system to produce an acceptable sound volume and to minimize degradation of engine power.
Further objects of exemplary forms of the present invention will be made apparent in the following Best Modes for Carrying Out Invention and the appended claims.
The foregoing objects are accomplished in an exemplary embodiment by an exhaust system baffling apparatus mounted within the side exhaust pipes of a vehicle. The baffling apparatus may include an elongated tube with an exhaust gas blocking portion, such as a cap or other sealing device, mounted to the forward end of the tube. The exhaust gas blocking portion is operative to direct exhaust gases to flow outside the tube rather than through the tube.
The baffling apparatus may further include a plurality of equally spaced flanges in surrounding relation around the tube. In the exemplary embodiment of the present invention the flanges have an outer edge with a rounded contour that corresponds to the inner circular contour of an exhaust pipe. The flanges may be in the form of a ring with a centrally located aperture and a radially extending slit. The slit extends from the aperture to an outer edge of the flange to give the flanges a C-shaped configuration. When mounted to the tube, the portions of each flange opposite the slit may extend radially from the tube and may be generally perpendicular to the tube. However, the opposed portions of each flange adjacent the slit may be curved generally away from each other and radially extend from the tube at non-perpendicular angles. For example, in an exemplary embodiment the edges of the flanges formed by the slits may extend in the radial direction at about 60 to 70 degree angles with respect to the longitudinal axis of the tube.
In an exemplary embodiment the C-shaped flanges may be formed by cutting a circular ring with a centrally located elliptical aperture and with a radial slit from a planar piece of sheet metal. The opposed ends of the circular piece of sheet metal may then be bent apart, such that one portion of the ring extends below and a second portion of the ring extends above the original plane of the ring. The flanges may be welded to the tube in a predetermined relationship along the tube with the flanges being equally spaced apart. In an exemplary embodiment all of the flanges may be orientated in the same direction with respect to the tube. In addition, the flanges may be positioned along the tube with gaps between adjacent flanges. In further exemplary embodiments the flanges may be progressively angularly offset from each other. For example, rather then having each slit of each flange being aligned, each flange may be positioned at a different angular position around the tube.
In an exemplary embodiment at least two of the flanges include a bracket member. The brackets are used to secure the apparatus to the inside of a side exhaust pipe in an orientation in which the closed or capped end of the tube faces the headers of the engine. To mount the apparatus to an exhaust pipe, the apparatus may be placed adjacent the outside surface of the pipe. Holes may then be marked and drilled through the exhaust pipe at locations which correspond to the brackets of the apparatus. The apparatus may then be inserted through one end of the exhaust pipe, such that the holes in the brackets are aligned with the holes through the exhaust pipe. Bolts may then be inserted through the holes in the pipe and the brackets to secure the apparatus within the exhaust pipe. In one exemplary embodiment at least one of the brackets may include threaded portions, such as a weld nut, to receive a bolt
In alternative exemplary embodiments the flanges may have other shapes, depending on the sound characteristics and baffling characteristics desired for the exhaust system. For example, an alternative shape for the flanges may include a spiral shape. In further exemplary embodiments the tube may include one continuous spiral-shaped flange which extends in surrounding relation along all or a portion of its length. In other exemplary embodiments, differently shaped flanges or flanges orientated in different directions may be attached to the tube to produce different sounds and performance characteristics of the exhaust system.
In further exemplary embodiments of the invention, the acoustical and dampening characteristics of the apparatus may be modified by perforating the tube and/or flanges with a plurality of relatively small holes. In addition, the acoustical and dampening characteristics of the apparatus may further be modified by placing relatively short slits through the flanges which do not extend all the way between the outer edge of the flanges and the aperture of the flanges.